Put an obvious dependency on browser from ui_test.

It is expected to fix flaky build failures in the BUG.

Using source code names, this CL adds a dependency
chrome/test/base/ui_test_utils.cc
--> content/public/browser/render_process_host.h

Other dependencies
content/public/browser/render_process_host.h
--> services/shell/public/cpp/interface_registry.h
--> out/Release/gen/services/shell/public/interfaces/interface_provider.mojom.h
are already written.

BUG=633077

Review-Url: https://codereview.chromium.org/2321563004
Cr-Commit-Position: refs/heads/master@{#417485}

chrome/test/BUILD.gn

@@ -330,6 +330,7 @@ if (!is_android) {
     deps = [
       "//components/metrics:test_support",
       "//components/os_crypt:test_support",
+      "//content/public/browser:browser",
       "//skia",
       "//testing/gtest",
     ]